Side-channel pump

ABSTRACT

The invention relates to a side-channel pump for transporting fuel in a motor vehicle. Said pump comprises a partial annular channel ( 11 ) located in housing sections ( 4, 5 ), said channel having a greater radius than a crown of vane chambers ( 10 ) that are located in the impeller ( 6 ). The vane chambers ( 10 ) and the partial annular channel ( 11 ) respectively have the same width. This prevents wear and tear to the sealing surfaces.

BACKGROUND OF THE INVENTION

The invention relates to a side-channel pump which is provided, inparticular, for the conveyance of fuel in a motor vehicle, with a rotorrotating in a pump casing, with a ring of blade chambers which isarranged in one end face of the rotor, and with a part-annular channelarranged opposite the ring in the casing and extending from an inlet toan outlet.

Such side-channel pumps are often used in fuel tanks of present-daymotor vehicles and are known from practice. The part-annular channel andthe blade chambers form a conveying chamber through which fuel isconveyed. When the rotor rotates, this gives rise, in a conveyingchamber, to circulation flows radially outward from the radially innerregion of the blade chamber, as seen from the axis of rotation of therotor.

The known side-channel pump has the disadvantage that, as seen from theaxis of rotation of the rotor, the flow can penetrate between the rotorand the casing in the radially outer region. The residual dirt containedin the medium leads to a wear of the axial sealing surfaces lyingradially outside the conveying chamber and therefore to a reduction inefficiency. This effect is additionally reinforced, in particular, byheavily contaminated medium to be conveyed.

The problem on which the invention is based is to design a side-channelpump of the type initially mentioned, in such a way that it avoids awear of the axial sealing surfaces of the conveying chamber.

BRIEF DESCRIPTION OF THE INVENTION

This problem is solved, according to the invention, in that the externalboundary of the part-annular channel has a larger diameter than theexternal boundary of the ring of blade chambers.

By virtue of this design, the main flow emerging from the blade chambersof the rotor cannot come directly up against the edge. Owing to thisdesign, dirt particles present in the medium pass only to a reducedextent into the region of the axial gap between the rotor and the pumpchamber. Consequently, in the pump according to the invention, the weardue to contaminated medium is markedly reduced. This ensures apermanently high efficiency of the side-channel pump according to theinvention.

According to another advantageous development of the invention, a wearof the axial sealing surfaces of the blade chambers in the inlet regionof the circulation flow can be avoided in a simple way if the internalboundary of the part-annular channel has a larger diameter than theinternal boundary of the ring of blade chambers.

The side-channel pump according to the invention acquires a particularlysimple structural configuration when the part-annular channel and theblade chambers have in each case the same width, and when the radius R1from the axis of rotation of the rotor to the part-annular channelexceeds the radius R2 of the ring of blade chambers by 0.1−1.5 mm. As aresult of this configuration, in each case the axial sealing surfaces ofthe blade chambers and of the part-annular channel are protected againstwear.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention permits numerous embodiments. To make its basic principleeven clearer, one of these is illustrated in the drawing and isdescribed below. The drawing shows a fuel pump in a single figure.

DETAILED DESCRIPTION OF THE INVENTION

The fuel pump has a side-channel pump 2 according to the invention,driven by an electric motor 1. The side-channel pump 2 has a casing 3with two casing parts 4, 5, between which a rotor 6 driven by theelectric motor 1 is arranged rotatably. An inlet 7 and an outlet 8 arearranged in the casing 3. The rotor 6 has on its end faces two rings ofblade chambers 10 delimited by guide blades 9. Blade chambers 10 locatedopposite one another are connected to one another. Part-annular channels11 are arranged, opposite the rings of blade chambers 10, in the casingparts 4, 5. The part-annular channels 11 extend from the inlet 7 to theoutlet 8 and, together with the blade chambers 10, form a conveyingchamber for the conveyance of fuel. The fuel to be conveyed thereforeflows through the side-channel pump 2 axially. When the rotor 6 rotates,this gives rise, in the conveying chamber, to circulation flows whichare accelerated away from the axis of rotation of the rotor 6 in theblade chambers 10. For illustration, the flows of the fuel are marked byarrows in the drawing.

The radius R1 of the part-annular channels to the axis of rotation ofthe rotor 6 is greater than the radius R2 of the ring of blade chambers10 by the amount X=0.1−1.5 mm. This avoids the situation where thecirculation flow, when it emerges from the blade chambers 10, strikesthe sealing surfaces of the part-annular channel 11. When thecirculation flow enters the blade chambers 10, the circulation flow islikewise kept away from the sealing surfaces of the blade chambers 10,said sealing surfaces facing the casing parts 4, 5. A wear of thesealing surfaces is thereby avoided.

1. A side-channel pump which is provided, in particular, for theconveyance of fuel in a motor vehicle, with a rotor rotating in a pumpcasing, with a ring of blade chambers which is arranged in one end faceof the rotor, and with a part-annular channel arranged opposite the ringin the casing and extending from an inlet to an outlet, characterized inthat the external boundary of the part-annular channel (11) has a largerdiameter than the external boundary of the ring of blade chambers (10).2. The side-channel pump as claimed in claim 1, characterized in thatthe internal boundary of the part-annular channel (11) has a largerdiameter than the internal boundary of the ring of blade chambers (10).3. The side-channel pump as claimed in claim 1 or 2, characterized inthat the part-annular channel (11) and the blade chambers (10) have ineach case the same width, and in that the radius R1 from the axis ofrotation of the rotor (6) to the part-annular channel (11) exceeds theradius (R2) of the ring of blade chambers (10) by 0.1−1.5 mm.